ARSENIC ] 



CHEMISTRY. 



381 



of heat in the form of the thermo-electric pile. (See 

 Bismuth). Its symbol is Sb ; its equivalent = 129 ; 

 and the specific gravity, 6 '8. Oxide of antimony is pre- 

 pared by mixing the chloride with a hot solution of car- 

 bonate of soda, by which a grey powder is produced. 

 This oxide, combined with tartaric acid and potash, 

 forms the "tartar emetic," used as a medicinal agent. 

 Antimonious acid, Sb O 4 , is a constituent of James' 

 powder, a well-known substance, employed in medicine. 

 Antimonic acid, Sb O 4 , is produced by acting on the 

 metal by means of strong nitric acid ; and forms salts 

 with bases. Sulphur and antimony, united as sulphides, 

 differ in appearance, in the native condition, from those 

 prepared artificially. The natural sulphide is a dense 

 black powder ; and is much used by firework-makers to 

 give coloured names. Its peculiarity in this respect may 

 be noticed by burning the following composition : 

 Nitre, four parts ; sulphur, two parts ; sulphide of 

 antimony, one part. 



Eacli ingredient is to be separately pounded, and 

 the whole is then to be intimately mixed in a mortar. 

 During combustion, the above produces an intense 

 light, and is used for the manufacture of Bengal lights 

 and sea-signals. We have frequently employed it for 

 the pxirpose of taking photographs at night. The arti- 

 ficial sulphide has a rich red colour, and may be pre- 

 pared by passing sulphuretted hydrogen tlirough a 

 solution of tartar emetic. 



Kermes' mineral is produced by boiling the sulphide 

 with potash or its carbonate, and has a reddish-browu 

 colour. A sulphide of antimony, containing five equi- 

 valents of sulphur to one of the metal, is produced by 

 passing sulphuretted hydrogen through a solution of the 

 perchloride in hydrochloric acid, when it falls as a yellow 

 powder. 



If a little powdered antimony be heated and dropped 

 into a jar of chlorine gas, it will take fire, producing a 

 chloride of the metal. If the black sulphide be boiled 

 with hydrochloric acid, the terchloride is formed (Sb Clj), 

 which has been called the " butter of antimony." This, 

 with olive oil, is used as a bronzing composition. 



Antimony, like arsenic, has the singular property of 

 combining with hydrogen, forming what is called anti- 

 moniuretted hydrogen. This may be procured by pass- 

 ing hydrogen through -iy solution of the metal. If a 

 cold plate be held against the flame of this compound, 

 metallic antimony will be deposited, which will not vola- 

 tilise on the application of heat a point of importance 

 as distinguishing it from arseniuretted hydrogen, of 

 which we shall have to speak hereafter. 



ARSENIC. 



THE ores of this metal are very widely diffused in com- 

 bination w ; th those of other metals ; and one of its 

 oxides is the well-known poison, commonly called white 

 arsenic. The importance of the subject of poisoning by 

 this substance, will require, on our part, a somewhat 

 extended notice of this element and its compounds ; and 

 ire shall enter into a general description of the various 

 methods w' ich have been proposed for their detection. 



The metal itself is obtain ijle from any of its combi- 

 nations by *irst applying heat say to the arseuiurets of 

 iron, copper, <tc. White arsenic, or arsenious acid, 

 sublimes ; and if this be heated with charcoal in a test- 

 tube, the metal can be readily procured as a crystalline 

 substance having a metallic lustre. Its equivalent is 

 75 ; symbol, As ; and the specific gravity about 6. 

 When heated and in process of volatilisation, arsenic 

 affords a smell resembling that of onions. We may 

 here warn our readers to be exceedingly cautious witli 

 respect to inhaling the vapour, as it produces extreme 

 inconvenience by acting on the membranes of the eyes 

 aud nose, even in minute quantities, and may prove 

 highly dangerous ii incautiously inhaled. 



Arsenious acid is the most important combination of 

 the metal. It contains one equivalent of arsenic to 

 three of oxygen ; and, as we have stated, is ' 

 known by tlie name of white arsenic. It is surprising 



that so deadly a poison should be so extensively em- 

 ployed. It has been stated, on good authority, that 

 the inhabitants of some parts of Germany are accus- 

 tomed to eat arsenious acid, and that it has the effect of 

 making them plump in body, and sustains their power 

 of ascending steep places, so far as the act of breathing 

 is concerned. It has also been remarked, that so long as 

 the habit is maintained, no inconvenience of any kind is 

 produced ; but if it be left off, then all the symptoms of 

 arsenical poisoning present themselves. White arsenic is 

 often given to horses, and produces a sleekness of skin 

 not obtainable by any other means. As a sheep- wash, 

 and to steep wheat, it is often employed ; and it is no 

 uncommon matter to find farmers purchasing the article 

 extensively on market-days, for the purposes we have 

 named. We need feel surprise, not that cases of arse- 

 nical poisoning so rarely occur, but rather that they are 

 not more frequent, when we take into account the cha- 

 racter of the individuals with whom it is entrusted. 

 Arsenic with copper forms a pigment largely used for 

 the purpose of printing a rich green colour on paper- 

 hangings. This fact, in the opinion of many, has given 

 rise to instances of poisoning in households, owing to 

 the arsenical powder being brushed off from the walls, 

 and being inhaled afterwards. Such an occurrence may 

 take place, undoubtedly, in extraordinary circumstances ; 

 but we are strongly inclined to the opinion, that an 

 accident only, and not a constant tendency, must exist 

 to produce harm from such a source. Ladies' dresses 

 have often their green tint heightened by means of 

 Scheele's green ; and persons employed in making such, 

 and in the manufacture of wax and other artificial 

 flowers, suffer seriously from the inhalation of arsenical 

 powder thus used in their business. It is much to be 

 regretted, that the personal charms of the belle must be 

 enhanced by her poorer sisters paying the cost with the 

 sacrifice of their health, and, possibly, their lives. 



In the early attempts to manufacture candles from 

 stearine, considerable difficulty was experienced in the 

 tendency towards crystallising, which that substance 

 always exhibited whilst cooling. White arsenic was 

 used for the purpose of preventing this, and it was suc- 

 cessful ; but great danger arose to persons sitting in 

 rooms wherein such candles were burned. Hence the 

 use of arsenic was given up, and, by mechanical means, 

 the difficulties we have named have been overcome. 

 Another source of danger to a family, is the use of 

 arsenic (by which term we shall in future call the 

 arsenious acid, for the sake of simplicity) as a poison 

 for rats and mice. To the ordinary observer, littlo 

 difference exists between flour and that substance ; and 

 to prevent the danger arising from this source, an act 

 of parliament has been passed, in which it is insisted 

 that the white arsenic shall not be sold in its ordinary 

 state, but mixed with other substances to give it a dis- 

 tinctive character. Another and extraordinary use of 

 this poison is that of a cosmetic. For this purpose, a 

 little of the white arsenic is put into the water in which 

 the person is washing, and the face and hands are 

 bathed with the solution. Independent of the certainty 

 that the dissolved matter will be absorbed by the pores 

 of the skin, small particles are likely to be introduced 

 into the mouth, nose, and eyes ; the least inconvenience 

 from which would be that of causing inflammation of 

 the membranes. But as the pores of the skin commu- 

 nicate wuh the blood- vessels, the poison is gradually 

 absorbed by the system, and the consequences of its use 

 soon become apparent by symptoms of arsenical poison- 

 ing, which supervene. 



We may suggest a very simple way by means of which 

 arsenic- may readily be distinguished from any other 

 substance usually found in our houses. Let a small 

 pinch of the suspected powder be placed at the end of a 

 penknife, and introduced into the flame of a candle. 

 If it be white arsenic, it will soon pass off as vapour ; 

 or a small portion may be placed on some red-hot coal, 

 when, if arsenic be present, it will volatilise, affording a 

 smell exactly like that of onions. 



We shall now procoed to familiarise the minds of our 



